problem-17.js

/**
 * Company: Google.
 *
 * Suppose we represent our file system by a string in the following manner:
 * The string "dir\n\tsubdir1\n\tsubdir2\n\t\tfile.ext" represents:
 * dir
 *  subdir1
 *  subdir2
 *    file.ext
 *
 * The directory dir contains an empty sub-directory subdir1 and a sub-directory
 * subdir2 containing a file file.ext.
 * The string "dir\n\tsubdir1\n\t\tfile1.ext\n\t\tsubsubdir1\n\tsubdir2\n\t\tsubsubdir2\n\t\t\tfile2.ext"
 * represents:
 * dir
 *  subdir1
 *    file1.ext
 *    subsubdir1
 *  subdir2
 *    subsubdir2
 *      file2.ext
 * The directory dir contains two sub-directories subdir1 and subdir2. subdir1
 * contains a file file1.ext and an empty second-level sub-directory subsubdir1.
 * subdir2 contains a second-level sub-directory subsubdir2 containing a file file2.ext.
 *
 * We are interested in finding the longest (number of characters) absolute path to a
 * file within our file system. For example, in the second example above, the longest
 * absolute path is "dir/subdir2/subsubdir2/file2.ext", and its length is 32
 * (not including the double quotes).
 *
 * Given a string representing the file system in the above format, return the length of
 * the longest absolute path to a file in the abstracted file system. If there is no
 * file in the system, return 0.
 *
 * Note:
 * The name of a file contains at least a period and an extension.
 * The name of a directory or sub-directory will not contain a period.
 *
 * Leetcode: https://leetcode.com/problems/longest-absolute-file-path/
 */
var lengthLongestPath = function(input) {
  const dirs = input.split('\n');
  let max = 0;
  let pathLen = Array(dirs.length).fill(0);

  for (const dir of dirs) {
    const stripDir = dir.replace(/(\t)+/, '');
    const depth = dir.length - stripDir.length;

    if (stripDir.includes('.')) {
      max = Math.max(max, pathLen[depth] + stripDir.length);
    } else {
      pathLen[depth + 1] = pathLen[depth] + stripDir.length + 1;
    }
  }

  return max;
};